(2000, NS 114)
Sven Britton, Gunilla Källenius and Jan Andersson
Nobel Forum, Karolinska Institutet, Stockholm
Proceedings: Andersson-Britton-Källenius: Prevention and Treatment of Tuberculosis, 2001, special issue of Scandinavian Journal of Infectious Diseases, Stockholm.
Participating in the symposium were 42 senior international lecturers as well as 27 younger researchers from developing countries representing four continents. The latter also presented their research, but in poster form. One hundred eighteen years after Koch's discovery of the tuberculosis bacterium and 80 years after the development of the BCG vaccine, the tuberculosis pandemic is still out of control. The World Health Organization (WHO) has estimated that about one third of the world's population is infected with TB. Ten million die of the disease. The BCG vaccine has a highly variable protective effect in different countries (0-80 percent). Despite intensive epidemiological and molecular biological research, the factors behind this are unknown. The vaccine's protective effect is lowest in poor countries, where 95 percent of the infected people are found. It has been etablished, however, that his weakened live-bacterium vaccine - the most heavily used vaccine in the world (300 million doses annually) - has mutated more than 30 of about 2,500 genes from its original form in the early 1950s.
The symposium examined the role of an adequate T-lymphocyte-mediated immune response in curing and providing protection against TB. The human immunodeficiency virus (HIV), which breaks down precisely this immunity, has paved the way for a new and devastating epidemic of HIV/TB co-infection, which is spreading very rapidly, especially in sub-Saharan Africa. This was described by African researchers at the symposium. Another new threat is the emergency of multi-drug resistant strains of TB, which has mainly affected southern and eastern Europe, Russia and the institutionalized, for example U.S. prisoners. This was described along with various ways of limiting the development of drug resistance. The development of new, stable, possibly DNA-based TB vaccines is the hope of tomorrow, but the researchers involved made it completely clear that we are still far from achieving this. Hygienic measures and carefuly monitored follow-up and treatment (Directly Observed Treatment, DOT) of TB cases is cost- and environmentally effective even today. This strategy is now spreading with WHO help to many poor countries, as WHO representatives and others reported.